A plug jack of a cell phone for an external component (such as a headphone, a USB etc.) in a related art includes a slot connected to a mainboard of the cell phone. The plug jack such as a headphone jack and a USB jack of the cell phone is a weak link in a static test and in a practical use. In the static test or the practical use, statics may enter into the mainboard of the cell phone easily through the plug jack, and then the cell phone may suffer a variety of display related problems. Meanwhile, due to the headphone jack or the USB jack of the cell phone, an internal circuit of the cell phone is in communication with the external environment of the cell phone. When the cell phone is wet by water, the water may infiltrate into the cell phone directly via the slot, which causes a short circuit and a corrosion of the internal circuit of the cell phone and results in damages on the cell phone.
At present, in order to prevent water from entering into the cell phone through the plug jack, the cell phone is usually added with a waterproof cell phone shell. However, it is unable to touch the cell phone when using the same, so the cell phone may not be convenient to be used. Alternatively, the headphone jack or the USB jack of the cell phone is added with a waterproof plug. However, the plug jack may not be convenient to be used due to the waterproof plug, and the waterproof plug is easy to be lost and has a poor anti-static performance in cell phone manufacturer's static tests.